CHATTANOOGA (AP) — Authorities in Tennessee have reopened an investigation into the slaying of a 10-year-old boy who was suffocated and left along a wooded trail 20 years ago.

The Hamilton County District Attorney’s Cold Case unit announced last week that the FBI would assist the office and Chattanooga police in a renewed investigation into the death of Joshua Walden.

Walden was last seen in December 2000 riding his bicycle around his neighborhood. His then 17-year-old sister, Crystal Walden, reported him missing and the child’s body was found the next day half a mile from his home, news outlets have reported.

Investigators determined the boy had been suffocated before acid was poured on the body.

The FBI will be sending members of its behavioral analysis unit and child abduction rapid deployment team to the area to pursue any new leads, Joe Carrico, special agent in charge of FBI in Knoxville, announced at a news conference Wednesday. Carrico called on members of the public to recall and report anything from that time that could help investigators.

One of the original homicide detectives on the case, Mike Mathis, said the department has sent evidence collected at the scene 20 years ago to the FBI to undergo fresh testing with new technology. Investigators declined to comment on any further details on the case.

Since the announcement Wednesday, the District Attorney’s office has posted a series of videos on social media produced by the FBI that officials said they hope will renew public awareness.

“I just need to know,” Crystal Walden pleads through tears in one of the videos, asking for tips that could help solve her brother’s case.